Calothrix nidulans Setchell & N.L.Gardner, 1924 (original description)
Calothrix nodulosa Setchell & N.L.Gardner, 1924 (original description)
Ceramium bicorne Setchell & Gardner, 1924 (original description)
Ceramium caudatum Setchell & N.L.Gardner, 1924 (original description)
Ceramium fimbriatum Setchell & N.L.Gardner, 1924 accepted as Gayliella fimbriata (Setchell & N.L.Gardner) T.O.Cho & S.M.Boo, 2008 (original description)
Ceramium horridum Setchell & N.L.Gardner, 1924 accepted as Ceramothamnion horridulum (P.C.Silva) M.J.Wynne & C.W.Schneider, 2023 (original description)
Ceramium johnstonii Setchell & Gardner, 1924 (original description)
Ceramium procumbens Setchell & N.L.Gardner, 1924 (original description)
Ceramium serpens Setchell & N.L.Gardner, 1924 (original description)
Chlorogloea regularis Setchell & N.L.Gardner, 1924 (original description)
Chondria acrorhizophora Setchell & N.L.Gardner, 1924 (original description)
Cladophora hesperia Setchell & N.L.Gardner, 1924 (original description)
Codium amplivesiculatum Setchell & N.L.Gardner, 1924 (original description)
Codium brandegeei Setchell & N.L.Gardner, 1924 (original description)
Codium simulans Setchell & N.L.Gardner, 1924 (original description)
Colacodasya sinicola Setchell & N.L.Gardner, 1924 accepted as Jantinella sinicola (Setchell & Gardner) Kylin, 1941 (original description)
Compsonema immixtum Setchell & N.L.Gardner, 1924 (original description)
Corallopsis excavata Setchell & Gardner, 1924 (original description)
Dicranema rosaliae Setchell & N.L.Gardner, 1924 (original description)
Ectocarpus gonodioides Setchell & N.L.Gardner, 1924 (original description)
Eucheuma johnstonii Setchell & Gardner, 1924 (original description)
Gelidiopsis tenuis Setchell & N.L.Gardner, 1924 accepted as Ceratodictyon tenue (Setchell & N.L.Gardner) J.N.Norris, 2014 (original description)
Gelidium decompositum Setchell & Gardner, 1924 (original description)
Gelidium johnstonii Setchell & N.L.Gardner, 1924 (original description)
Gracilaria crispata Setchell & Gardner, 1924 (original description)
Gracilaria lacerata Setchell & Gardner, 1924 (original description)
Gracilaria pachydermatica Setchell & Gardner, 1924 (original description)
Gracilaria pinnata Setchell & N.L.Gardner, 1924 (original description)
Gracilaria subsecundata Setchell & N.L.Gardner, 1924 (original description)
Grateloupia howei Setchell & N.L.Gardner, 1924 (original description)
Gymnogongrus carnosus Setchell & N.L.Gardner, 1924 (original description)
Hydrocoleum codicola Setchell & N.L.Gardner, 1924 (original description)
Hypnea johnstonii Setchell & Gardner, 1924 (original description)
Kallymenia pertusa Setchell & Gardner, 1924 (original description)
Laurencia johnstonii Setchell & N.L.Gardner, 1924 (original description)
Laurencia obtusiuscula Setchell & N.L.Gardner, 1924 (original description)
Laurencia obtusiuscula var. corymbifera Setchell & Gardner, 1924 (original description)
Laurencia obtusiuscula var. laxa Setchell & Gardner, 1924 (original description)
Polysiphonia marchantiae Setchell & N.L.Gardner, 1924 (original description)
Polysiphonia sinicola Setchell & Gardner, 1924 (original description)
Pringsheimia marchantiae Setchell & N.L.Gardner, 1924 accepted as Ulvella marchantiae (Setchell & N.L.Gardner) R.Nielsen, C.J.O'Kelly & B Wysor, 2013 (original description)
Prionitis abbreviata Setchell & N.L.Gardner, 1924 (original description)
Sargassum acinacifolium Setchell & N.L.Gardner, 1924 (original description)
Sargassum cylindrocarpum Setchell & Gardner, 1924 (original description)
Sargassum herporhizum Setchell & N.L.Gardner, 1924 (original description)
Sargassum horridum Setchell & N.L.Gardner, 1924 (original description)
Sargassum johnstonii Setchell & N.L.Gardner, 1924 (original description)
Sargassum johnstonii f. gracile Setchell & N.L.Gardner, 1924 (original description)
Sargassum lapazeanum Setchell & N.L.Gardner, 1924 (original description)
Sargassum polyacanthum f. americanum Setchell & N.L.Gardner, 1924 (original description)
Sargassum sinicola Setchell & N.L.Gardner, 1924 (original description)
Schizymenia johnstonii Setchell & Gardner, 1924 (original description)
Schizymenia violacea Setchell & N.L.Gardner, 1924 (original description)
Sphacelaria brevicornis Setchell & N.L.Gardner, 1924 (original description)
Xenococcus deformans Setchell & N.L.Gardner, 1924 (original description)